The invention relates to a system and method of computer assisted surgery (CAS) using stereotactic navigation with three-dimensional visualization, and more specifically to a CAS system that is reactive and does not disrupt operating room workflow procedures.
A current method of inserting implants (consisting of, for example, a plate and associated screws) is typically accomplished by positioning the plate on the corresponding anatomical location and inserting the screws with the assistance of fluoroscopy. The implantation of plating and nailing systems is often a difficult task because operating room (OR) procedures are generally minimally invasive and thus placement is achieved by trial and error using fluoroscopy such as a C-arm apparatus, i.e., C-arm vision. This generally leads to long operating times. Furthermore, during such a procedure, both the patient and the operator are exposed to significant amounts of radiation.
In addition, in some cases it may be impossible to determine the position of implant components (for example, the screws in the bone) with sufficient precision because the fluoroscopic image is only two-dimensional. This may lead to misplacement or insertion of screws of improper length. This, in turn, may cause high revision rates or even injuries (e.g., hip joint injury). In order to ensure that these implant components do not extrude from the bone, it is thus sometimes necessary to position these implant components with an excessively large margin of error away from the edge of the bone. In many instances, the result is that the implant cannot be positioned as intended, and the desired biomechanical stability cannot be achieved. In the case of femoral neck fractures, for example, the use of conventional fluoro-navigation does not result in any significant improvement.
Other cutting edge technologies currently being used in operating rooms to assist in surgery include intra-operative three-dimensional (3D) imaging and navigation systems based on tracking technology. However, only a few hospitals are using these technologies. The limited adoption of these technologies is primarily due to their high cost, the effort involved in installing these systems, and the significant resulting changes to OR procedures or workflow. For example, tracking technologies require a line of sight between the tracking device and navigation detection system. This disrupts the normal workflow since the surgeon and other personnel must then remain cognizant of the system's line of sight requirements.
Further, as a general matter, satisfactory positioning of a main implant, like a plate or nail, cannot be defined pre-operatively. For example, during an operation positioning can be done by haptic match on the bone surface or by reaming the bone to make space for an intra-medullary nail. In addition, although the position of sub-implant(s) might be based only on pre-operative images (e.g., fluoroscope or CT images), such position is still relative to the position of the main implant. Thus, a positioning procedure cannot be completely planned pre-operatively, but must be optimized during the operation. In this regard, classical stereotaxis cannot be used due to the fact that the position cannot be predefined.
Accordingly, there is a need for a computer assisted surgery (CAS) system that enhances surgical procedures without significantly disrupting the normal OR workflow. More specifically, there is a need for a combined 3D imaging and CAS system which can be easily and readily integrated into the clinical environment. Preferably, such a system would be low cost, easy to set-up and use, and minimize changes to the OR workflow.